AJP - Cell Physiology, Vol 265, Issue 3 C733-C739, Copyright © 1993 by American Physiological Society
Structural changes in the apical membrane of lamprey chloride cells after acclimation to seawater
H. Bartels, H. Schewe and I. C. Potter
Abteilung fur Zellbiologie und Elektronenmikroskopie, Medizinische Hochschule Hannover, Germany.
Freeze-fracture replicas demonstrate that the apical membrane of the
chloride cells of young adult lampreys (Geotria australis) undergoes a
structural change when the animal is acclimated from freshwater to
seawater. Although the particles on both the P face and the E face of this
membrane are randomly distributed in freshwater animals, they are usually
arranged in clusters on both fracture faces in seawater-acclimated animals.
Light optical diffraction analysis demonstrates that the particles forming
the clusters are periodically arranged. Although comparable clusters of
particles have not been recorded in other epithelial membranes that are
engaged in transporting ions into a hypertonic environment, they may be
involved in the final step of Cl- secretion by the chloride cells of
lampreys in seawater.
